In many commercial buildings and manufacturing facilities, heavy metal doors are often utilized for purposes of security, fire doors, or serve as containment doors between an enclosure having a negative air pressure relative to an environment on an opposing side of the door. Frequently, the requirements and operating environment of the door are such that a force in excess of 50 pounds is needed to set the door in motion. For example, there may be a pressure differential between opposite sides of the door which increases the force needed to set the door in motion. Such pressure differentials can be intentional or can be transient events such as the result of operation of an internal HVAC system.
For safety reasons, the amount of force human operators need to apply to a door should never exceed 50 pounds of force and new doors may be limited by building codes to as little as 30 pounds of force. While foot or hand operated levers have been utilized to assist in door opening operations, such designs are frequently prohibited by safety codes because it requires two manual actions to operate the door. It remains a need in the art for a passive door assistance-opening device that compensates for a door weight or pressure and automatically operates upon initiation of a normal door opening sequence. Accordingly, there remains room for variation and improvement within the art.